The HPA
week 3 report on influenza in the UK shows a dramatic jump in fatal
cases (to 254 from 112), which has more credibility than earlier
reports, which were trailing the numbers reported by the media (and
the media reports represent a small fraction of the total number of
deaths). Agencies are now withholding the number of fatal cases,
so the actual number of deaths remains murky. Media reports
describe young patients who have flu-like symptoms, which then develops
into pneumonia and death, but cases are said to have died from “natural
causes”, suggesting the number of flu deaths is markedly higher than
the deaths withheld by hospital administrators.

Moreover, the latest HPA report has a dramatic jump in the deaths of
the elderly (>64) to 55 from 16 reported through week 2. The
number of elderly deaths is now markedly higher than the number of
influenza B deaths (16), indicating most of the elderly deaths are now
due to H1N1.

In the past, the elderly were generally spared from H1N1 because of
seasonal H1N1 infections when they were much younger.
Consequently, more than 90% of H1N1 fatalities have been under 65 and
initial UK reports indicated that all H1N1 deaths this season were
under 65. This recently reported increase in deaths in the
elderly population could signal a dramatic change in H1N1 deaths.

Usually deaths in the elderly are not lab confirmed. The patients
are frequently in long term care facilities and die at the
facility. No samples are collected and the number of deaths is
extrapolated from death certificates and descriptions of flu-like
conditions or pneumonia. Thus, the current number of elderly
deaths may also be markedly higher than then 55 lab confirmed cases in
the week 3 HPA report. The report includes a graph of deaths in
the UK, which is well above expected levels.

The latest sequence data on recent H1N1 isolates in the UK
as well as other countries in the northern hemisphere (Mongolia,
Iran, Japan, Russia, United
States) documents the emergence of a new sub-clade with
S188T. The dominance of this sub-clade indicates it is escaping
immunological defenses, and this escape may now include responses to
earlier seasonal H1N1 infections by the elderly population.

More information on the H1N1 isolated from elderly patients would be
useful.